There are generally two types of grape harvesters, as characterized by its picking head (e.g., apparatus which is anchored to the frame of the harvester and used to dislodge fruit from fruit-bearing plant, vine and/or tree): (1) a bow rod shaker harvester and (2) a trunk shaker harvester. A bow rod harvester typically includes a head assembly with a set of flexible bow rods (or beaters) that are situated on both sides of a vine (or tree) row. In operation, the bow rods strike the canopy at high speed or shake the canopy in order to dislodge the fruit. As such, bow rod harvesters may also be referred to as canopy or foliage shakers. Bow rod harvesters are typically used when the vines are young with trunks that could be severed or severely damaged with the use of a trunk shaker harvester. See, e.g., U.S. Pat. No. 6,145,291 to Jarmain.
A trunk shaker harvester typically includes a head assembly with two parallel rails (or bars) that are situated on each side of a vine (or tree) row. The rails are perpendicular or nearly perpendicular to the vine trunk. In operation, the trunk shaker head is moved side to side (e.g., oscillating like a pendulum about an axis parallel to the direction of travel of the harvester), allowing the rails to shake the vine trunk. For example, the trunk shaker head moves the vine with grape berries to the right, in a direction perpendicular to the vine row, and while the grape berries are moving to the right, the head reverses direction, causing the berries to dislodge from the vine. See, e.g., U.S. Pat. No. 4,286,426 to Orlando et al.